PostgreSQL 10 implements SQL standard's IDENTITY
In SQL Server is quite common to use IDENTITYs for non-natural primary keys. In PostgreSQL, until version 10, only SERIALs could be used for the same purpose. But that has changed.
Why INDENTITY and not SERIAL and SEQUENCES?
This post can be found in a Jupyter Notebook in my Github.
This could be a good script as a starting point to export data from Oracle to MongoDB. It can be modified easily to add some row transformations (like combining columns) or other things.
- pymongo version: 3.4.0
- cx_Oracle version: 6.0.2
- PyMongo: Fast . . .
powershell doesn't have native support for yaml. Solution: PSYAML and powershell-yaml
YAML is not supported by default in powershell like JSON and XML, although some people are already asking for it in github and Windows user voice (give your voice, too!). YAML is more comfortable for human reading than JSON.
Currently there're two maintained modules to work with YAML:
Posted in: powershell
How to check consistency at the end of a transaction
DEFERRED CONSTRAINTS are useful when you know that in a transaction you'll have inconsistent data for a while, like foreign keys that don't match, but you know that at the end of a transaction it will be consistent.
It was a nice PostgreSQL surprise to discover
DEFERRED CONSTRAINTS, because it's not present in many . . .
Changing normal SQL Server's behavior
Microsoft defines the trace flags as:
Trace flags are used to temporarily set specific server characteristics or to switch off a particular behavior.
The purpose of trace flags is to change a SQL Server default behavior. The context they apply to can be global, session or query and it depends on the nature of the flag. For . . .
Posted in: sqlserver
In Microsoft documentation for OleDbEnumerator.GetRootEnumerator() method
there's a C# example how to list all Ole DB Providers. I've just rewritten it in Powershell, creating a function that returns a list of providers, so it's easier to work with and can be filtered.
It's useful to check which providers are installed in a . . .
Using hostnames in pg_hba.conf
Since PostgreSQL 9.1 it's possible to use host names in pg_hba.conf.
I'm using it in a server and I got this error from a Java's client application trying to connect to it:
Caused by: org.postgresql.util.PSQLException: FATAL: no pg_hba.conf entry for host "192.168.1.2", user "my_user", database . . .